The Role of Stimulus Structure in Human Memory

Long-term memory retention has long been seen as primarily or exclusively being driven by the meaning of stimuli. Three memory paradigms are reviewed that demonstrate the importance of stimulus structure in memory. First, memory is influenced by orthographic distinctiveness. Stimuli that have unusual spelling patterns are more likely to be processed as individual stimuli than are items that are less distinct. This may either enhance or degrade memory performance, depending upon the nature of the test that is given. Second, the phenomenon of recognition without identification shows that orthographic features can be effectively used as retrieval cues even when the attempted retrieval of a stimulus' name and meaning ends in failure, preventing use of semantic cues. Third, the pseudoword effect, the higher rate of positive responses to pronounceable nonwords than to words, is a demonstration that adding meaning to orthographic features may lead to a reduction of familiarity. Structural features can play an important role in long-term retention.